Ethanol is one of the most widely consumed drugs with resultant profound consequences to individuals and society. The current methodology used to measure ethanol concentration in breath relies on decades old technology and may limit development of breath analysis to detect not only ethanol with great specificity, but also a number of other compounds that appear in breath. Therefore, the overall goal of the present grant is to prepare the scientific foundations and an actual prototype of a new generation of breath-analysis equipment and software to address the public health needs of the twenty-first century. This proposal describes the current and proposed activities of a multi-disciplinary team of physical and medical scientists who are evaluating use of a mini-gas chromatograph (mini-GC) device and exhaled breath condensate (EBC) collected using active breath management as alternative matrices for real-time, point-of-use measurement of ethanol concentration with preservation of samples for later analysis, if necessary. The applicants have constructed a mini-GC modified to detect ethanol in a real-time manner with excellent specificity that can accurately discriminate between ethanol and other molecules (e.g., acetone, methanol, toluene) that may interfere with alternative technologies used to detect ethanol in breath. Using novel breath handling techniques that gate breath collection to end-tidal carbon dioxide concentrations, we show that ethanol appears in the EBC, at concentrations similar to those measured in blood, following oral consumption of alcohol (3-5 ounces). The appearance of DNA in EBC alludes to the possibility of a "self-identifying tag" to reliably and accurately link an EBC sample to an individual subject source. The goal of this proposal is to expand these findings to refine, construct, and examine the performance characteristics of a mini-GC coupled to an EBC collector. To that end, the following specific aims will be achieved: Specific Aim 1: Design and build a mini-GC device coupled to an EBC collector with active breath management that reliably measures ethanol concentrations in real-time collects and preserves EBC for later analysis. (Milestone: Availability of device by 10/15/2007). Specific Aim 2: Correlate gaseous and EBC ethanol concentrations measured by this device in human subjects with concentrations found in venous blood and document the absence of oral fluid contamination during several different temperatures, normal or hyperventilating breathing patterns, and with/without active breath management. (Milestone: Completion of performance data by 12/31/2007). The short term objective of Xhale Diagnostics, Inc. is to develop these devices to a market of $70 million. The long term objectives of the investigators are to develop breath-based detection technology to enable medical diagnostics as sheltered by intellectual property licensed from the University of Florida. [unreadable] [unreadable] [unreadable] [unreadable]